Galaxy Clusters and the Life and Death of the Universe

The distribution of galaxies in the universe is patchy. Galaxies are bound together in clusters made of stars, hot gas and invisible dark matter. These galaxy clusters are part of a cosmic web of filaments, nodes and empty voids that has been building up over 13 billion years. How do we observe this structure, and how do we use gravitational lensing and satellite X-ray observations to measure its mass? How do galaxy clusters trace the past expansion of the universe and reveal our future? This lecture will highlight data from the Dark Energy Survey, today’s largest cosmic survey, to answer these questions.